Retort arrangement



June 4, 1957 F. M. MORA RETORT ARRANGEMENT 3 Sheets-Sheet 1 Filed Aug. 12, 1952 INVENTOP, Je a jo' M F. M. MORA RETORT ARRANGEMENT June 4 1957 3 Sheets-Sheet 2 Filed Aug. 12, 1952 V INVENTOR.

F ERNANDO MAR/0 129 BY 4 P W ATTORNbY b11164, 1957 MQRA RETORT ARRANGEMENT 3 Sheets-Sheet 3 Filed Aug. 12, 1952 9 I v INVENTOPI B7 0PM United States Patent RETORT ARRANGEMENT Fernando Mario Mora, Buenos Aires, Argentina Application August 12, 1952, Serial No. 334,024

15 Claims. (Cl. 202-117) The present invention relates to the carbonization of wood and is more particularly directed to apparatus including a retort for eflecting the said carbonization.

There are already several processes known which use ditferent equipments for :carbonizing wood. In most of the cases, these equipments have been designed for a specific purpose. Thus in the common wood carbonization plants most of the gases arising from the carbonization are sent to stack. This is due to the fact that the gases which are produced in wood carbonization are very complex mixtures of compounds which require, in order to be separated, purified and rectified, a costly equipment for which usually independent power must be provided so that the outfit is uneconomical.

Thus, the present invention is directed to the production of a series of products from wood as the starting material and a plant for carrying out the conversion, which plant may operate continuously to produce charcoal. i

'More particularly, the present invention provides a retort for carbonizing wood in which the wood is carbonized within a substantially vertical container disposed. within a heat insulated housing. The container is divided into a plurality of superposed chambers by means of a plurality of superposed removable horizontal pan els and means are provided to remove the panels to permit the material in any of the chambers to pass downwardly toward the chamber immediately therebeneath. Conduit means are provided for collecting the gaseous products which are produced in the chambers and the container is heated to effect the carbonization, this heating being preferably effected by the passage of heating gases through an annular chamber defined between the.

container and the housing. More preferably, the container is surrounded by a helical structure so that the heating gases are more effectively employed.

More preferably, the height of the carbonizing container is held to a minimum by positioning the panels to define chambers which decrease in height from an upper relatively large chamber to a lower relatively small chamber. The top portion of the carbonizing container is provided with an opening for the admission of wood to be carbonized and the admission opening is controlled by the provision of an admission panel. A considerable saving in fuel economy is effected by providing a wood drying and preheating tunnel in communication with the wood admission opening.

The heat-ing gases which leave the upper end of the annular space between the container and the housing are' passed through the wood drying and preheating tunnel and the tunnel is provided with screens to'counteract' the tendency of the hot gases to remain in the upper portion of the tunnel. The invention includes the manner in which the charges of wood to be carbonized are conveyed through the tunnel to the wood admission opening.

More particularly, the container or tower for carbonizing wood is provided with an upper primary chamber for receiving a charge of material, a secondary chamber arranged below the primary chamber and a bottom chamber positioned below the secondary chamber and the removable panels are constructed to slide through a slot in the tower surrounded by a pair of semi-circular rings. The panels are provided with ears and a screw arrangement is employed to effect the horizontal sliding which, is desired.

The full scope of the invention will be more fully apparent from the description thereof taken in conjunction with the accompanying claims.

An object of the present invention is the provision of a novel retort adapted for the efiicient carbonization of wood in the form of lumps.

Another object is to provide a number of retorts for, wood carbonization, which in a preferred structural em-' bodiment are all related through a preheating tunnel and special charging control means are provided for said retorts.

Still another object is to provide a gas collecting system for collecting the gases produced in the retorts.

A further object is to provide a special type of retort.

which enables the charging thereof at the same time as the carbonization continues and whereby no substantial losses of calories or heat are produced.

Another object is to provide a retort discharging sys-. tem for the resulting charcoal and a special cooling equipment for said charcoal in connection with said preheating tunnel.

Another object is to provide a preheating tunnel which enables the lumps of wood to be submitted to substantially complete drying action, and a preheating action by the retort heating gases whereby a considerable fuel economy and time economy are obtained.

Another object is to provide a retort having a high useful space factor.

Still another object is to provide a retort which requires a low fuel consumption for heating purposes.

Another object is to provide a retort or an equipment of retorts, the cross-section of which is such that in relationship with the heat transmission coefiicient the wood of the central part of the retort is rapidly carbonized.

A still further object is to provide a retort divided into a number of superposed chambers, which permit reduction of the total operative period of one charge in said retort.

Another object is to provide a wood preheating tunnel in such a relationship with the retorts that the heat.

ing, drying, preheating and carbonization of the wood is carried out in successive and progressive form at an adequate speed.

to the next thereby improving the uniformity of carbonization.

These and further objects and advantages of'the present invention will become evident during the following 3 description in which, in order to facilitate the understanding of the invention reference is made to several figures showing by way of example two of the preferred embodiments of the plant.

in the drawings:

Figure 1 is a schematic side elevation, partly in section, of the admission and of the preheating tunnel with its instrumentalities and accessories in one of its preferred embodiments.

Figure 2 is a schematic side elevation, partially in section, of a plant constructed inv accordance with the invention.

Figure 3 is .a schematic detail, inside elevation, of the coupling and driving mechanism of the basket waggons in the specific embodiment shown in the precedingfigu'res.

Figure 4 is a side elevation, partly in section, and showing some of the details of the wood lcarboniaing retort.

Figure 5 is a bottom plan 'view of a basket-Waggon. Figure 6 is a schematical side elevation, partly in section, of another preheating tunnel arrangement,

Figure 7 is a detail in said elevation of a'coupling device.

Figure 8 is a detail in side elevation of the stop device shown'in Figure "6.

Fig. ,9 is a cross-section taken through the wood carbonizing retort of Fig. 4 .at a level'just beneath the panel 69 and looking upward toward the 'said panel.

It is desired to point out that the description which follows is illustrative of the invention and presents preferred embodiments of the invention, it being understood that the present inventionis intended to include those variations which will become apparent to those skilled in the art from the description which follows.

It is considered convenient to place the plant of the present invention near the forest or artificial plantation 'to be carbonized, or if this is not possible, near a transport station. In either case it is advisable to build a broad rail net for the wood transport-waggons or basketwaggons 1 (see Figure 1), which will be lated explained, which are able to transport lumps of wood of an adequate size for the wood carbonizing retorts and for feeding the plant on such'a scale as to avoid interruptions in the operation of the plant.

'7 The rail net should lead towards an admission door 2 of an ante-chamber 3 of a wood drying and preheating tunnel '4 (see Figure 1), later on identified as preheating tunnel.

" Each of the basket-waggons 1 comprises a platform 5 supporting a basket 6 of sufficiently strong structure for transporting a considerable charge of wood 7, the volume of which should preferably be equal to that of a primary chamber 66 of a retort 41 (see Figures 2and 4), as will be explained later on. It is advisable that the baskets 6 be so built that they provide the largest possible spacings, called contact surfaces, for the lumps of wood 7, so that said-lumps may contact the drying and preheating gases of preheating tunnel 4, as will be seen in due time.

Platform 5 of each basket-Waggon 1, 'as may be better seen in Figure 5, is provided on its lower face 8 with two pairs of bearings 9 supporting axles10 having wheels 11. Platform 5 is provided at its central part with a discharge door 12 linked to the platform 5 by hinges 13, which allow said dischargedoor 12 to open in the way shown inFigure 2. The middle part of said discharge door 12 supports at its lower face, as may be seen in Figure 5, a pair of bearings 14 by which a pin 15 is rotatably supported and on which a control wheel 16 for said discharge door '12 is mounted.

. -It can thus be understood that the net of rails for the basket-waggons 1 requires besides the pair of conventional rails for the wheels 11, a middle rail for the control wheel 16. If the middle rail is removed .and v provided that the Waggon 1, or at least the partcorrespond 4 ing to the discharge door 12 is positioned above an adequate cavity, said discharge door 12 will automatically open and the charge of wood 7 will be discharged from said Waggon 1 into said cavity which, as will be seen later on, is the primary chamber of a retort 41.

Each basket-Waggon 1 comprises furthermore a coupling projection 17 mounted on the lower face 8 of platform 5 and coaxially with the control wheel 16 and at the front end of said Waggon 1.

Finally each Waggon 1 'is provided with automatic coupling devices 20 (see Figure 7) mounted on the front 18 and back 19 of the basket 6. Usually the automatic coupling device 20 corresponding to the back 19 is mounted at a greater height from platform 5 than the coupling device 20 corresponding to the front 18, in order to facilitate the coupling between two aligned waggons 1. This coupling device 20 consist of a bar 21 the posterior end of which is swingably supported by a pivot 22, the ends of which are housed in suitable supports 23 mounted on the front 18 and back 19 of the basket 6. The front end of bar 21 is of a special hook-shape type 24 which has an upper coupling surface 25 and a lower coupling surface 26, the latter being farther away from pivot 22 than surface 25. A cam surface 27 and a sliding surface 28 form the front endof said special hook 24. It is convenient to cut down the linking end 29 of the lower coupling surface 26 and the sliding surface 28 in order 'to' avoid wear and tear. The heights of the coupling surfaces 25 and 26 should be substantially equal and sufiicient to prevent two coupled waggons 1 from uncoupling themselves when passing over uneven surfaces. -A stop 30 is arranged above the supports 23 for preventing the hook-shape coupling 24 dropping too low.

In order to couple two aligned basket-waggons 1 by means of their coupling device 20, it is only necessary to bring-them together so that the sliding surface 28 of the coupling device 20 corresponding to the back 19 of the basket 6, will slide over the cam surface 27 until the lower coupling surface 26 engage the other coupling surface 25 of the other Waggon; in other words they will adopt the position shown in Figures 1 and 7. Figure I shows only a few waggons of the train, the rest of which corresponding to .the inclined portion 43, has not been" shown. It is obvious .that during the coupling, the coupling device corresponding to the back 19 of basket 6 will oscillate about its pivot22.

Thus, a train of waggons 1 can easily be formed, which train is directed towards the admission door '2 of the preheating tunnel 4 (see Figure '1), for subjecting the lumps of wood 7 to the carbonization process.

The carbonizing retorts 41 which will be described later on (see Figure 2), are arranged in at least one row and the heating gasesare passed on the outside of said retorts 41 for heating them and for carrying out the carbonization of the wood arranged inside said retorts 41. The heating gases are collected by the preheating tunnel'4 'for drying and preheating the wood in the basketwaggons 1 which move slowly in said preheating tunnel 4 Thus the previous statement made, that it is .important to.provide baskets 6 which provide the greatest possible access space 'for ensuring good contact between the drying and preheating gases and the lumps of wood, can'now be understood.

7 The percentage f water contained in the different types ofwood is of considerable importance forthe carbonization. Said water in said wood produces two important drawbacks, of which the first one consists inthe necessity of evaporating it as far as possible before subjecting the wood .to carbonization, and the second is that the dilution of the resulting pyroligneous acid from the condensation of the evaporated water entails an increase in fuel cost and time for its distillation which is very important.

Thelheating of the wood produces up to approximately nothing but water and therefore from the economical and industrial viewpoint it is convenient to eliminate said water before subjecting the wood to the actual carbonization process.

It is possible to dry the wood economically without requiring any special fuel expenses for that purpose by taking advantage of the waste calories of the combustion gases resulting from the retort heating and from the other heating systems of the plant and cooling equipment for the charcoal. In order to achieve this result said hot gases are forced to pass through the wood in the basket-waggons 1, before they reach the chimney 44.

By means of that previous drying action it is possible to introduce the lumps of wood substantially dehydrated into the retorts, which produces the following advantages:

(a) A considerable reduction in fuel expenses for heating the retorts, which amounts approximately to 50%, since the required calories for evaporating the water which the wood contains is almost equal to the calories which are required for its complete carbonization.

(b) The time of carbonization is reduced to approximately 50%, that is to say that the efiiciency of the retorts is doubled.

(c) The condensing apparatus are reduced by approximately 30%, as far as the refrigerating surfaces are concerned, with the consequent economy in cooling water for the refrigeration.

(d) The pyroligneous acid is approximately 50% more concentrated which also represents an economy on the apparatus and equipments for treating said pyroligneous acid specially in the latter part of the process where it is transformed mainly into acetone, as will be later explained.

To carry out this previous drying and preheating of the lumps of wood in the plant of the present invention, a wood drying and preheating tunnel 4 is built of reinforced concrete duly insulated to avoid as much as possible any loss of heat by radiation. The basket-waggons 1 with their charges of wood advance inside said tunnel 4 at such a speed that the run is accomplished in approximately 18 to 20 hours, which time is necessary for substantially dehydratingthe wood and preheating it to approximately.

150 C. It is obvious that the required time varies in accordance with the condition in whichthe wood is and the type of wood used. The preheating tunnel 4 is provided along its entire length with screens 31 which counteract the tendency of the hot gases to remain in the upper part of the arch of the tunnel 4, and bearing in mind the displacement of the gases towards the chimney 44, these screens 31 produce an undulatory movement of the gas flow whereby a longer path of the gases in the tunnel 4 is obtained and at the same time the temperature in each cross-section of the tunnel 4 is more uniform.

The flow of the hot gases is in opposite direction to the advance of the waggons 1. Thus the gases which are more saturated with humidity are precisely where they should be and that is at the starting point of the path of the waggons 1 in the preheating tunnel 4, which is the part where the wood is still very damp. Due to this arrangement the drying action of the hot gases on the wood is not too quick and the surfaces of the lumps of wood do not contract whereby the evaporation of the water from the core part of the lumps of wood is also perfectly wel achieved.

In order to avoid the entry of substantial air masses from the outside towards the inside of theprehe-ating tunnel 4 during the successive entries of the basket-waggons 1 into said preheating tunnel 4, the latter is provided with the ante-chamber 3. This antechamber 3 comprises an admission door 2 (see Figure l) which connects the outside with the inside of the preheating chamber and a dividing panel 32 which separates the preheating tunnel 4 from the antechamber 3. The length of the antechamber 3 is slightly greater than the length of awaggon 1.

However, if it is desired to charge simultaneously two or, more successive waggons into the preheatingtunnel 4, 75 combination with a. coupling and driving mechanism 47' it would only be necessary to provide an antechamber'S of suitable length and the operative apparatus of the disengaging mechanism 33 would have to be varied, as will be understood immediately.

The disengaging mechanism 33, only schematically shown in Figure 1, consists for instance of a telescopical' tube which may rise and push bar 21 of the posteriorcoupling device 20 of the Waggon 1, upwardly at a point adjacent its pivot 22. When the telescopic-a1 tube rises,

bar 21 rises about its pivot 22 and uncouples Waggon 1 from its immediately following one. Immediately thereafter the disengaging mechanism 33 drops again to its in-' operative position. At the same time the finger 34 of a chain driving mechanism 35 engages the coupling pro- 'It is obvious that instead of a chain 38 and gears 36 and 37 any other adequate type of driving means may be used.

Once the basket-Waggon 1 has entered antechamber 3 the admission door 2 is closed again, whereby the inside of said antechamber 3 is substantially isolated from the outside.

The dividing panel 32 has at its lower central part a slot 39 :which allows the passage of the coupling device 20 of the basket-Waggon 1 which last entered the antechamber 3 even though the dividing panel 32 is closed and bearing in mind that the driving mechanism 35 displaces the Waggon v1 in the antechamber 3 towards said panel 32, its front coupling device 20 will couple said Waggon to,

the back coupling device of the Waggon in front of it and already housed in the preheating tunnel 4, which coupling is performed in the way as previously described.

When the finger 34 during its movement reaches the driving gear 37 it uncouples the driving mechanism from the projecting stop 17 and operates a switch (not shown) which in turn operates a commanding device (not shown),

for raising the dividing panel 32 and thus allowing the entrance of the last wagon just coupled to the train of,

waggons, into the interior of the preheating tunnel 4. Said finger 34 continuous its movement and operates afterwards at the exact moment a second switch (not shown) which closes the dividing panel 32 at the same time as it stops the movement of the driving mechanism during a short time prior to starting the following operation similar to the one described, which time is necessary in order to advance the train of waggons in the tunnel 4.

The preheating tunnel 4 comprises an upper platform portion 49 (see Figure 2) which is a substantially horizon-.

tal section into which in the embodiment here described debouch all the upper ends of the retorts 41 a substantially horizontal base portion 42 (see Figure 1) which is adjacent to the dividing panel 32 and an inclined portion 43.

relating the base portion 42 with the upper portion 40 and completing the tunnel 4.

The chimney 44 is arranged above the base portion 42 and allows, the exit of the gases to stack.

As new basket-waggons 1 are added to the train of waggons inside the preheating tunnel 4, the waggonswhich have discharged their load into the retorts 41 must be also lowered to earth. With regard to the way of discharging the load of the waggons 1, an explanation will be given in due time when the retorts 41 are described.

Taking it, therefore, for the time being, that the empty waggons 1 reach the end portion 45 of thepreheating tunnel 4, these waggons 1 are lowered to earth by means of a lift 46, schematically illustrated, which operates in which is the source for advancing the train of basketwaggons 1 inthe preheating tunnel 4. I a

a This coupling and driving mechanismconsists as-may best be seen in Figure 3 of a driving shaft 48 connected to a-driving source (not shown) for instance an electric motor, and'on which driving shaft a pinion 49 is mounted which meshes with'a gear 50 mounted on a shaft 51'whichfurther supports gear 52 meshing with a rack 53. A reductor and inversor mechanism :(not shown)'is arrangedin between the driving source and shaft 51, by means of-which it is possible to displacesaid rack along both directions of a horizontal line to-which end said rack isconveniently guided. A hook-54 which has at its lower free end a sliding surface 55' is linked to one'end of said rack 53. A stop 60 integral with said rack 53 prevents-said hook 54from descending more than desired. It will be understood that when'said rack 53 is moving forward through a space formed by the lift shaft 56 passing through the lift cabin 59 which is at that moment in theposition' shown in Figure 2, and penetrates through a slot 58in an exit door 57, said'slot 58 being similar to slot 39 of the dividing panel '32"(see Figure 1), so that the slidhigsurfacedd slides over the cam surface 27 (see Figure 3) until itcouples the basket-Waggon 1.

Once the rack 53 has reached the limit of its 'forward movement, the direction of movement is reversed and at the same timeth'e exit door '57 (see Figure 2) is opened in a similar way as dividing panel 32 (see Figure 1), whereby the coupling and driving mechanism 47, moves the train of wag'gons '1 through a distance substantially equal to the length of onewaggon 1 and thereby entering the coupled empty Waggon 1 into the cabin 59. When said empty Waggon 1 is located in said cabin 59, as shown in Figure 2, the backward movement or stroke of the rack 53" has reached its end. At this moment the cabin 59 starts'its downward movement in its shaft 56, whereby said empty Waggon is automatically uncoupled from the rest of the train and the coupling and driving mechanism 47. If desired the lift 46 may be controlled automatically by means of a relay (not shown) which closes the circuit for the lift motor 46 when the rack 53 reaches the end of its return stroke. The lift motor 46 is synchronized with the driving source of the coupling and driving mechanism 47, so that cabin 9 of lift 46 will reach the ground and after having been discharged, the empty Waggon has still suficienttime to raise the cabin 5? again to its upper position, or in other words the position shown in Figure 2, before the coupling and driving mechanism 47 starts to enter the next empty Waggon in said cabin 59.

' The exit door 57 has a purpose similar to that of the dividing panel 32 (see Figure 1) that is to say, it tends to avoid the loss of considerable volumes of preheating gases coming from the heating channel of the retorts 41.

As has already been explained, in this embodiment of the plant of the present invention a plurality of aligned retorts 41 are provided, so that all the upper parts of said retorts debouch into the upper platform portion 40 of the preheating tunnel 4. The number of retorts 41 depends on the productive capacity of the plant and on the type of wood used. Should the productive capacity of the plant be very high, it is convenient to arrange several parallel rows of retorts 41 with a corresponding net of rails for the basket-waggons 1. Each of said retorts 41 is provided with a gas collecting tube 61 for collecting the gaseous products which are separated from the wood during the distillation and said collecting tubes 61 end all in a general collecting duct 13% which forwards the distilled products to a tar separator 62 to which reference will be made later on.

As may be best seen in Figure 4, each retort 41 is arranged inside a housing of refractory material 63. A

channel 64 is arranged between the outside of said retorts.

61 and the housing 63 through which pass the heating gases produced in a furnace 65.

- Eaehretort .41" is formed of a primarychamber 66, .a secondary chamber 67 and .a .final chamberfifi. .Eachof said chambers is separable from the-others by amovable panel of similar structure. In order to identify said panels, pancl 85 .will be called the admission panel, which separates the tunnel 4 from the inside of the primary chamber 66, the first panel, which is panel 469 separates the primary. chamber 66 from the secondary chamber 67; the second panel, which is panel'll separates the secondary chamber 67 from the final chamber -68 and the dischar e panel which is panel 71'separates the bottom of the final chamber 68 from adischarge space-72. Although the following-description-of one of said-panels will be made mainly with regardto the first panel 69, his understood that the remaining -panels 70, 7-1- and 85 are of similar structure with the exceptionof panel'85 which includes a further accessory, as-will be seenlater on. 1

As can be seen in Figs. 4 .and 9, the cylindrical wall of each retort 41 is provided at theheight of the dividing panels and, in the particular case under consideration, of the first panel 69, with a semicircular upper ring- 73 and a semicircular lower ring 74 parallely spaced from each other so that the corresponding .part of the edge of the panel 69 is capable of penetrating thereinto.- The cylindrical wall of the retort 41 is furthermore provided with a semicircular slot 75 so that the panel 69 may be withdrawn from .theintezior of the retort 41. To this end the panel 69 is provided with at least two cars 76 (only one of which is visible in the drawings) which support a crossblock 77. One end portion .78 of a screw 80 passes through said cross-block 77 and-is provided at its free end with a tension head (not visible) which is rotatably held by said block '77. A .duct -81 linked by its inner end 79 to the retort 41 passes through the chamber 64 .and' housing 63 towards the outside. The outside end 82 of said duct 81 is provided with a gasket 523 and a screw threaded bushing 83 forming a nut for the'screw 80. The gasket 523 isolates the interior of the duct 81 fromthe outside. A hand wheel 84 enables to operate the screw 80 and to remove the. panel 69 so as to establish a connection between the primary chamber 66 and the secondary chamber 67. j 7

The primary chamber'66 is isolated from the preheating chamber 4 by the admission panel 85, the structure and operation of which is similar to the panels 69 to 71 with the addition of an accessory in itsmiddle part which 7 accessory consist of a piece of rail 86 for the control wheel 16.

If the primary chamber 66 has to be charged with a new charge of lumps of wood (and it is understood that to this efiect said chamber 66 is empty) the hand wheel 34 is operated so as to withdraw the admission panel 85 together with its piece of rail 86 whereby the next basketwagon 1 which will pass over the retort 41 under consideration, will open its discharge door 12 as shown in Figure 2 and thereby discharge its contents into the primary chamber 66.

A hopper 87 prevents lumps of wood from falling into the gas channel 64 when a basket-Waggon 1 discharges its content into a primary chamber 66 of a retort 41. As has already been explained, it is preferable that the charge of wood of one Waggon 1 fill the space or volume of the corresponding chamber 66. Upon the Waggon 1 continuing its movement, with its discharge door 12 opened, the latter will be automatically closed by means of a cam 88 (see Figure 2) arranged inside the retort 41. Once the primary chamber 66 is charged and after the train of waggons has continued its displacement, the corresponding hand wheel 84 is operated to close the primary chamber 66 by means of the admission panel 85, whereby the following waggons will pass over said retort 41 without opening their discharge door 12.

Once the admission panel 85 is closed, the first panel 69 is opened to a small extent, so as to establish communication between the primary chamber 66 and the 'secondarychamber 67, for a purpose which will be later explained.

Between the upper part of the final chamber 68 and the lower part of the secondary chamber 67, an exterior duct 89 is provided which connects the said two chambers 67 and 68. Part of said exterior duct 89 passes through the channel 64 through which the heating gases produced in the'furnace 65 rise, sothat the distilling gases produced by the wood under carbonization in final chamber 68, which pass through exterior duct 89 to the secondary chamber 67 do not condense while flowing through said exterior duct 89.

The section 89 of said exterior duct 89, which section corresponds to the secondary chamber 67, is provided. with a prolongation 96. A sliding valve 91 is displaceably mounted in said prolongation 90 and separates the exterior duct 89 from the outside. During the carbonization, inspections must be made as will be seen later on, as to whether the wood housed in the final chamber 68 has concluded its carbonization process, which inspections are carried out by shifting the slide 92 towards the sec-' tion 89 of the exterior duct 89 as shown in broken lines, whereby the gases which are produced in the final cham ber 68, if still produced, pass out through said prolongation 90. On the other hand if the carbonization is concluded no gases will leave the prolongation 90 and the absence of gases indicates to the operator that the car bonization of the wood housed in the final chamber 68 is concluded.

In order to obtain the maximum eflficiency of the heat-l ing gases produced in the furnace 65 for heating said retorts 41, chamber 64 is provided with a helix 93 which forces the gases to displace themselves helically around: each retort, and after concluding the helical path said gases enter the preheating tunnel through the openings. 94 arranged between the outer face of the hopper 87 and the housing 63. i

The carbonization process is carried out as follows:

It is undersood that upon first starting the operation of the retorts 41 or after an interruption in the operation, the three chambers 66 to 68 must be successively charged with lumps of wood and the panels should be closed with the exception of the first panel 69, which should be slightly opened so as to establish communication between the primary and the secondary chambers 66 and 67, respectively." The heating gases produced in the furnace 65 which enter.

the channel 64 pass sufiiciently slowly therethrough in order to release a large part of their calories for carbonizing the wood. Once the charge of chamber 68 is com-' pletely carbonized, it is discharged.

The explanation of whereto the charcoal which passes through the opening corresponding to the discharge panel '71 is discharged will be given later on. s

It is obvious that the heating gases rising from the furnace 65 transfer part of their heat during their path towards the openings 94. When entering the channel 64 they will transfer the first part of their heat which is at? mary chamber 66 which is less carbonized than the charge which was passed from the secondary chamber 67 to the final chamber 68 will be passed from the primary chamber 66 to the secondary chamber 67. The first panel 69 is again closed after the charge has passed and the admission panel 85 is opened, whereby a new charge from a basket-Waggon 1 is introduced into the primary chamber 66. Once the primary chamber 66 is filled with;

wood, the admission panel is again closed, obviously after the Waggon 1 has discharged its contents and continued its movement for a suflicient distance sothat cam 88 has closed, the discharge door 12. The first panel' 69. is opened to a small extent in order that the gases which are produced by the wood in the primary chamber 66 may .pass to the secondary chamber 67.

Intermittent inspections are carried out to ascertain the state of carbonization in the final chamber 68, by means of the sliding valve 91, as previously explained, and as soon as the carbonization is concluded, the content of the final chamber 68 is discharged by withdrawing the discharge panel 71, to which end the corresponding hand-wheel is operated. Once the charcoal of the final chamber 68 has been discharged, panel 71 is closed again and the semicarbonized wood of the secondary chamber 67 is passed to the final chamber 68 and a similar operation is carried out with regard to the wood which has only started its carbonization in the primary chamber 66 and which is passed to the secondary chamber 67 whereby the primary. chamber 66 is again empty and the above described steps are repeated.

As has already been stated, the gases which are produced during the distillation in each retort 41 are 0014 lected by the corresponding collecting tube 61.

The vertical retorts 41 herein proposed have several advantages, such as the facility of charging and discharging them with regard to the currently used horizontal systems which consist of large and long horizontal retorts wherethrough basket-waggons charged with wood pass very slowly. This layout has several drawbacks such as that the free spaces which remain between the wood inside the basket-waggons and the walls of the retort are very large, which is partially due to the fact that the horizontal retort must have such cross-sections so as to allow the passage of the wood with the Waggon through it. In other words the ratio between the volume of wood and the volume of the retort is very low. Furthermore, in the horizontal arrangement it is a really diflicult proposition to lead the hot gases through said horizontal retorts in such a way as to obtain uniform heat distribution. Bearing in mind the above drawbacks, it is necessary:

(a) That the wood stay for a longer time in the retort than it might.

(b) The productive capacity charge space of retort is smaller than that of the equipment herein proposed.

(0) The fuel cost for carbonizing is higher because the ratio of the volume of the horizontal retort with regard to the volume of wood under carbonization is lower, nevertheless said retort must be at substantially the same temperature.

(d) In view of the fact that during the wood carboni zation, tar is distilled, it often happens that parts of said tar drop on the bearings of the basket-Waggon wheels seizing up the shafts in the bearings and producing derailments in the tunnel with the obvious consequences.

Comparingthe above drawbacks with the only advantage of said horizontal system, that it is possible to car bonize larger lumps, the vertical system herein proposed is found to be more convenient, since the fact that it is possible to use larger lumps of wood in a horizontal system is only a relative advantage because it should not be forgotten that it is easier to charge small lumps of wood (for instance, 35 cm. long and up to say 15 or 20. cm. diameter) into the basket 6 of the Waggon 1 than to arrange large pieces of wood on the special waggons for the horizontal system.

It is advisable to use in the retort equipment according to the present invention cylindrical retorts having a diameter not exceeding approximately 1.50 m. because the heat transmission coefiicient towards the longitudinal axis of each retort 41 decreases considerably when the? diameter of the retort is increased, and this would pro-- duce the following drawbacks: 7 i

for an equal volume of 1 l i (a) More time needed for complete carbonization. (b) It is possible that in the core part corresponding .to the longitudinal axis half carbonized pieces of wood remain which decreases the quality of the charcoal.

Even though it is possible to use vertical retorts having a single chamber or two chambers with which it would also be possible to carryout the process of the present invention, retorts having at least three chambers are preferred for the following reasons:

If the retort were to comprise a single chamber, the distilling gases would be sent to the chimney 44 (see Figure 1) during the step of charging said retort, with the consequent loss of said distilling gases and the risk of an explosion; furthermore after having charged such a single chamber retort with wood, complete carbonization' thereof must be effected before said retort can be discharged, which requires considerably more time than if a retort of three chambers is used, and thus decreases the efliciency of the equipment, because after a certain time the volume of semicarbonized wood is smaller than the volume of the charge of wood when charged into the single chambered retort and thereby an appreciable portion of the chamber is empty, which in other words means, that it does not work.

If a retort of two chambers were to be used, the same drawback as to the empty part of the chambers as explained above in connection with the single chambered retort exists, although on a smaller scale. Furthermore, bearing in mind that the heights of the two chambers are greater than the chamber heights of a three chambered retort of the same total height, the interval between discharge and discharge of charcoal is larger due to the fact that the upper part of the lower chamber of a two chambered retort .has a temperature considerably smaller than the upper part of the third or final chamber of a three chambered retort.

Another advantage of a retort having superposedchambers in accordance with the present invention is that the lumps of wood after entering into the primary chamber 66 are shifted .twice, the'first time when passing from the primary chamber 65 to the secondary chamber 67 and the second time when passing from the secondary chamber 67 to the final chamber 68. During the shifting, the lumps of wood under carbonization change their individual positions whereby some kind of stirring up of the lumps occurs which enables more uniform carbonization to be obtained due to the compensating differences in the heat intensities at the new positions which the lumps occupy after redistribution. These facts are of considerable importance because both an economy in the hours of carbonization as well as a more uniform charcoal is obtained. It has to be pointed out, that these movements of the lumps of wood when passing from one chamber to the next chamber do not involve breakages of importance because the lumps of wood when passing from the primary chamber 65 to the secondary chamber 67 have always started to carbonize and when in'that condition the knocks they receive usually can not break .said lumps. Similarly when the lumps pass from the secondary chamber 67 to the final chamber 68, the carbonization is not yet completed so that the breakages if any .are not of substantial importance.

Furthermore it has to be pointed out, that the three chambered retort has the advantage of maintaining the production substantially constant, which is very important especially as far as the volume of gas .producedis concerned. Similarly the lumps of wood gradually increase their temperature during the time the process requires for completion, starting from the moment of penetrating into the; preheating tunnel 4- until they are discharged as charcoal. The time of the process depends on the -typeof wood used; an average is 30 hours. The progressive temperature increase has a remarkable influence on the size of the resulting charcoal as well ason its friability and its mechanical strength.

The final chamber 68, where the carbonization is con cluded, will be at approximately 650 to 500 C., which is a good guarantee 'for the total carbonization and the elimination of pitch substances whichdecrease the value of the charcoal. The secondary chamber 67 will be at approximately 500 to 350 .C. and the :primary chamber 66 will be at a temperature of approximately 350 to 200 C. The preheating channel 4 will be at approximately 180 C. in the section corresponding to the upper platform 4%) which is the part of the tunnel immediately above each retort l1 .and at a temperature of approximately 60 C. in the base section 42 which is the part corresponding to the exit of the gases through chimney 44. Anybody skilled in the art will understand that the progressive temperature increase constitutes an ideal solution of the problem of obtaining high quality charcoal, to be achieved.

The retort heating gases which pass to the tunnel 4, are produced in the furnace .65, which comprises a gas burner therefor (see Figure 4). The gas for said burner 95 is produced in the plant of this invention and constitutes also a wood carbonizing by-product, as will be seen later on. A grid 96 is however provided in the furnace 65 to enable the burning of additional lumps of wood,-in case a larger amount of calories is desired to be forwarded than that which the gas burner 95 is capable of providing, which is for instance the caseduring the starting up period of the plant. The furnace 65 is divided by a panel 97 into a combustion chamber 98, in which thegas burner 95 and thegrid 96 is housed anda heating chamber99 connected at their respective upper parts by meansofa duct 100. A tar cracking cylinder 101 and a calcium acetate thermic decomposition cylinder 102, forming part of my copending applications Serial Nos. 304,023 and 304,025 as well as Patent No. 2,621,150 granted tome on December 9, 11952, are housed in said heating chamber 99. p 7

A pipe 103 connects the furnace 6'5 with thechannel 64 of each retort 41, to which end saidpipe 103 opens into a ring duly insulated by an-instilatinglayer'lOS of the retort, said ring itidhaving a series of openings 1 06 connecting said ring 104 with said channel 64. The-panel 97 has an internal conduit 107 connecting the combustion chamber 9% by means of the openings 108 and-109 with the pipe 1%. A register 1110 enables the flow of the gases through said conduit 167 who controlled. On the other hand, the heating chamber 99 is also connected to the pipe 103 through an opening 111 provided with a register 112. By suitable setting of the registers and 112, the fiow of the heating gases towards channel 64' may be duly controlled.

Returning now to the discharge of the charcoal when opening the discharge panel 71 (see Figure 2) the charcoal falls onto a conveyor 113 preferably a metallic conveyor, provided with a plurality of charcoal transporting buckets 114 for transporting and raising the charcoal in the vertical section of tunnel 115 and to discharge the charcoal ontoa horizontal conveyer 116, which preferably extends partially overthe charge openings 117 of charcoal cooling silos 11S, arranged in rows within common concrete chambers 119. Each silo 118 is provided at its upper part with an upper panel 120 controllablefrom the outside by means of ahandwheel '121and a lower panel 122 also controllable from the outside by means of a handwheel 123 for discharging the charcoal from the silos 118 once it is cooled oh.

a Each silo 1184's in functional relationship'with an inclined panel 124 which may be inserted in'the path of the horizontal conveyor 116 and is inserted after opening the upper panel 120 of the corresponding silo which inclined panel 124 forces thereby the red-hot charcoal (approximately at 300 C.) into the corresponding silo 118. Once said silo is fully charged, the inclined panel 124 is lifted and the upper panel 120 is closed and a similar process is carried out for charging another silo. It is important that the tunnel 115 is substantially perfectly shut off from the outside in order to avoid the entry of air, because the atmospheric oxygen would produce the immediate ignition of the charcoal.

The concrete chamber 119 has in its base portion 125 a plurality of openings 126 which enable the admission of cooling air into said chamber 119 for cooling 01f the charcoal contained in the silos 118, which air is extracted from the upper part of said chamber 119 by an extractor 127 which sends the hot air through the transport duct 128 into the middle part (not shown) of the inclined section 43 of the preheating tunnel 4. The base 125 is positioned at a certain height above the ground 129 so as to enable to lodge under the lower panel 122 a Waggon or a train (not shown) for receiving the cooled off charcoal from said silos 118.

As has already been explained, the gaseous products which are separated from the wood during its carbonization in the retorts 41 are collected by the collecting tube 61 (see Figures 2 and 4) and are led to the main collector pipe 130 of larger cross section, which leads said gaseous products into the tar separator 62, and more particularly described in my copending application Serial No. 304,026.

Instead of supplying a preheating tunnel 4 with the retorts 41 and their respective accessories, the arrangement shown in Figure 6 may be used thereinstead, which arrangement or equipment is more economical because the basket waggons 1 do not require the coupling device 20 nor the coupling and driving mechanism 47, with their special hooks 24.

In this embodiment, as in the previous embodiment deback bumpers 573 (only one bumper visible of each pair) of the conventional type in waggons. Both pairs of bumpers 577 and 575, are located at the same height with regard to the rails.

The drying and preheating tunnel 579 differs from tunnel 4 of the previously described embodiment in that it provides a slide gradient and thus entering into the earth, which has the advantage that once a Waggon 576 is entered into the antechamber 555 and once the chain driving mechanism 575 has opened the dividing panels 574, which are not provided with a slot, that the said gradient is sufiicient to allow the Waggon 576 to move forward in the preheating tunnel 579 until its front bumpers 577 engage the back bumpers 578 of the preceding Waggon. The several waggons reach thus one by one, due to gravity, the end portion 579' of the preheating tunnel 579 where a pair of rails 589 is provided with a stop device 581 formed of a pair of rail pieces 582 (only one visible) resiliently mounted on a plurality of compression springs 583 capable of displacing said pair of rail pieces 532 upwardly until their respective projections 584 engage corresponding ears 585 mounted on the rails 589 as shown in Figure 6, whereby the stop device 581 stops each waggon 576 as it reaches the end of its path corresponding to the preheating tunnel 579.

The preheating tunnel 579 is connected to an elevator channel 586 in which a lift cabin 587 is slidably mounted having a platform 58% with a pair of rails 589 with the same gradient as the pair of rails 580. Said pair of rails 589 are each provided with a projection 59! capable of depressing the stop device 561 when said cabin S7 reaches its lowermost position whereby one of said waggons 576 may enter said cabin 587.

The opposite end of the pair of rm'ls 589 is provided for example with a stop device 591, similar to the stop device 531, which prevents the waggons 576 housed in the cabin 587 from leaving the latter until said cabin 587 14 reachesthe upper endof its path. Said cabin is transported by the lift engine 592 and its accessories. A projection 593, similar to projections 590 depresses the stop device 591 when the cabin reaches its upper position,

so that said Waggon 576 may leave the cabin 587, as will be later explained.

When the cabin 587 reaches its upper end position, it will, by means of its platform 588 which enters into sealing engagement with the closuremember 594 formed of the concrete of the lift channel, seal off the upper end portion 586 from the rest of said lift channel 586.

This is of fundamental importance because the charge opening 595 of the retorts 596 in this embodiment, opens to atmosphere and the waggons 576 when leaving the cabin 587, after opening of the dividing panel 597, enter into the atmosphere and are partially covered by a roof 598. The discharge system of the wood contained inthe waggons 576 'is the same as that of the previous embodiment described, but it has to be pointed out that the path of the rails in the upper part 599 above the retorts 596 is also provided with a slide gradient, whicheliminates the necessity for a coupling and driving mechanism; the upper part 599 is connected to lift shaft 609- in which a discharge cabin 239 for empty waggons is' provided similar to elevator 46 in the previous embodi-' ment described.

The fact that the upper part 599 is in contact with the atmosphere, implies a number of advantages with regard to the other embodiment, because it is possible to control by sight the discharge of the waggons and the charging of the retorts. the preheated wood of the waggons is in contact with atmosphere, prior to being charged into the retorts, this exposure to air is of no substantial importance.

In view of the fact that the charge openings 595 of the retorts 596 are in contact with the atmosphere, it is obvious that the heating gases must be conducted in a different way as far as their discharge into the preheating tunnel 579 is concerned.

To this end the retorts are provided in their upper portion with a collector duct 156 'for the heating gases which enter into the lift channel 586 below the closure member 594 which gases pass through said lift channel 586 and enter the preheating tunnel 579 from where they are sent to stack through chimney 238;

Bearing in mind that when the cabin 587 is not in its upper position, the lift channel 586 is substantially completely cut off from atmosphere by its panel 597, the

gases supplied by collector duct 156 do not enter in con tact with the atmosphere.

When the lift cabin 587 reaches the upper end of its path, and upon opening of the panel 597, the isolation of the gases from the atmosphere is still maintained due.- to the fact that the platform 583 is in sealing engage ment with the closure member 594.

The upper part 599 is provided at its end adjacent tolift shaft 600 with a panel 601, synchronized with cabin 239 which avoids that the waggons 576 may leave said space between said tower and housing, an upper primary chamber for receiving a charge of material, a secondary chamber arranged below said primary chamber, a bottom chamber positioned below said secondary chamber, gas collecting tubes connected to said secondary and bottom chambers, a slide panel interposed between each pair of chambers, a pair of semi-circular rings arranged on each side of each panel, there being slots in said tower for the slidable movement therethrough of said panels, a

plurality of ea rs'secured to each of said panels, a cross block secured to said cars, a screw having an end por- Bearing in mind the very short time which 15 tion arranged in engagement with said cross block, a head arranged on the outer end of said screw, and a duct surrounding said screw and extending through said housing and said tower.

- 2. A retort for carbonizing wood comprising a heat insulated housing, a substantially vertical container for wood carbonization disposed within said housing with the exterior of said container spaced from the interior of said housing to define an annular chamber therebetween, means to pass heating gases through said annular chamber, a plurality of superposed removable horizontal panels dividing said container into a plurality of superposed chambers, conduit means for collecting gaseous products communicating with a plurality of said chambers, means to remove said panels to permit the material in said chambers to pass downwardly to the chamber immediately therebeneath, said container being provided with a top portion having a wood admission opening and admission panel for controlling said wood admission opening, a wood drying and preheating tunnel in communication with said wood admission opening, said heating gases leaving said annular space at the upper end thereof and passing through said wood drying and preheating tunnel, said tunnel be ing upwardly inclined toward said admission opening, releasibly connected waggons for conveying charges of wood and means to haul said waggons through said tunnel.

3. A retort for carbonizing wood comprising a heat insulated housing, a substantially vertical container for wood carbonization disposed within said housing with the exterior of said container spaced from the interior of said housing to define an annular chamber therebetween,

means to pass heating gases through said annular'cham her, a plurality of superposed removable horizontal panels dividing said container into a plurality of superposed chambers, conduit means for collecting gaseous products communicating with a plurality of said chambers, means to remove said panels to permit the material in said chambers to pass downwardly to the chamber immediate- 1y therebeneath, said container being provided with a top portion having a wood admission opening and an admission panel for controlling said Wood admission opening, a wood drying and preheating tunnel in communication with said wood admission opening, said heating gases leaving said annular space at the upper end thereof and passing through said wood drying and preheating tunnel, said tunnel being downwardly inclined toward said admission opening, and freely movable unconnected waggons for conveying charges-of wood through said tunnel.

4. A retort for carbonizing wood comprising a heat insulated housing, a substantially verticalcontainer for wood carbonization disposed within said housing with the exterior of said container spaced from the interior of said housing to define an annular chamber'therebetween, means to pass heating gases through. said annular cham her, a plurality of superposed removable horizontal panels dividing said container into a plurality of superposed chambers, conduit means'for collecting gaseous products communicating with a plurality of said-chambers, means to remove said panels to permit the material in said chambers to pass downwardly to the chamber immediately therebeneath, said container being provided with a topportion having a wood admission opening and an admission panel for controlling said wood admission opening, a wood. drying and. preheating tunnel in communication with said wood admission. opening, said heating gases leaving said annular space at the upper end thereof and passing through said wood drying and preheating tunnel, waggons for conveying charges of wood through said tunnel, said'waggons comprisinga platform, a basket mounted on said platform, a discharge door in said platform for discharging lumps of wood carried in said basket, and means for controlling the; opening and closing of said discharge door, 7

5. A retort for carbonizing wood as recited'in claim 3 in which said tunnel is formed in two sections interrupted by a lift shaft and the space above said wood admission opening is open to the atmosphere.

6. A retort for carbonizing wood as recited in claim 4 in which said discharge door is hinged to said platform and opening and closing ofsaid discharge door is effected by means of a control wheel supported by said door and adapted to run on a control rail.

7. A retort for carbonizing wood as recited in claim 4 in which said baskets have a front end and a back end, a coupling device supported by each of said ends, said coupling device of said back end being located at a greater height with regard to said platform than said coupling device of said front end.

8. A retort foncarbonizing wood as recited in claim 4 in which said preheating tunnel comprises an antechamher, a base portion, an inclined portion and a platform portion, said base portion having a first end and a secend end, said first end of said base portion being connected to said antechamber, said inclined portion comprising a third end and a fourth end, said third end of said'inclined portion being connected to said second end of said base portion, said platform portion comprising a fifth and sixth end, said fifth end of said platform portion being connected to said fourth end of said inclined portion, a chimney connecting said base portion with a stack, an empty basket-Waggon discharge lift connected to said sixth end of said platform portion, a train of basket-waggons housed in said drying and preheating tunnel and means for moving said train.

9. A retort for carbonizing wood as recited in claim 8 in which said discharge lift comprises a lift shaft con- 7 nected to said fixed end of said platform portion, a cabin slidably housed in said lift shaft, and a removable discharge panel separating said sixth end of said platform portion from said lift shaft.

10. A retort for carbonizing wood as recited in claim 9 in which said means for moving said train is located behind said lift shaft, and adapted to pass through said lift shaft, cabin, and discharge panel into said platform portion. 7

11. A retort for carbonizing wood as recited in claim 4 in which said preheating tunnel comprises an antechamber, a first gradient portion having a first end and a second end located at a lower level than said first end, said antechamber being connected to said first end of said first gradient portion, a first lift shaft connected to said second end, a first cabin in said first lift shaft, a second gradient portion located above said retort arrangement, said second gradient portion having a third end and a fourth end located at a lower level than said third end, a second lift shaft, said third end being connected to said first lift shaft, said fourth end being connected to said second lift shaft, said third end being located above said second end, and a second cabin slidably housed in said second lift shaft.

12. A retort for carbonizing wood as recited in claim ll in which said antechamber is provided with a removable admission door and a removable dividing panel separates said antechamber from said first end. 7

13. A retort for carbonizing wood as recited in claim ll in which Waggon stop means are provided at said second end, said stop means being controllable by said first cabin.

14. A retort for carbonizing wood as recited in claim 13 in which Waggon stop means are provided in said first cabin, said last named stop means being controllable by said third end.

ii A retort for carbonizing wood as recited in claim 12 in which said first lift shaft comprises an upper part and a lower part, sealing means in said lift shaft, said first cabin being adapted to enter into sealing contact with said sealing means and thereby sealingly separate said upper part from said lower part, and a connection communicating between the space between said housing and said container and at least the said lower part of said first lift shaft.

References Cited in the file of this patent UNITED STATES PATENTS 5 Stroback Jan. 23, 1912 MacRae June 4, 1918 Dressler Sept. 23, 1924 Ljungdahl Oct. 19, 1926 10 Trumble June 19, 1928 18 Parker Oct. 16, 1928 Suida Jan. 1, 1929 Day Sept. 20, 1932 Wilson Oct. 3, 1933 Sperr Sept. 18, 1934 West et a1 Mar. 2, 1937 Berry Sept. 27, 1938 FOREIGN PATENTS France July 4, 1918 France June 20, 1927 

1. IN A CARBONIZING RETORT, A VERTICALLY DISPOSED HOUSING, A TOWER ARRANGED IN SAID HOUSING, AND PROVIDING A SPACE BETWEEN SAID TOWER AND HOUSING, AN UPPER PRIMARY CHAMBER FOR RECEIVING A CHARGE OF MATERIAL, A SECONDARY CHAMBER ARRANGED BELOW SAID PRIMARY CHAMBER, A BOTTOM CHAMBER POSITIONED BELOW SAID SECONDARY CHAMBER, GAS COLLECTING TUBES CONNECTED TO SAID SECONDARY AND BOTTOM CHAMBERS, A SLIDE PANEL INTERPOSED BETWEEN EACH PAIR OF CHAMBER, A PAIR OF SEMI-CIRCULAR RINGS ARRANGED ON EACH SIDE OF EACH PANEL, THERE BEING SLOTS IN SAID TOWER FOR THE SLIDABLE MOVEMENT THERETHROUGH OF SAID PANELS, A PLURALITY OF EARS SECURED TO EACH OF SAID PANELS, A CROSS BLOCK SECURED TO SAID EARS, A SCREW HAVING AN END PORTION ARRANGED IN ENGAGEMENT WITH SAID CROSS BLOCK, A HEAD ARRANGED ON THE OUTER END OF SAID SCREW, AND A DUCT SURROUNDING SAID SCREW AND EXTENDING THROUGH SAID HOUSING AND SAID TOWER. 